1. Field of the Invention
This invention relates to a method for drilling holes in soil or rock, especially for producing prestressed ground anchorage, and drilling equipment for carrying out said method.
2. Description of the Prior Art
Drilling equipment for producing holes for prestressed ground anchorage in soil or rock is known. Such equipment has a crawler truck with a carriage mount connected to articulated arms in such a way that it can be pivoted in all directions in space. A magazine for several lengths of pipe of the drill column is provided on such a drilling tool. The drive for the drill column with the drill bit can be raised and lowered on the carriage and mechanically transfers each length of pipe of the drill column from the magazine. After drilling the holes and before introducing the prestressed ground anchorage, the lengths of pipe of the drill column are returned to the magazine. A disadvantage of this system is that a borehole that can also hold casings to support the wall of the borehole cannot be drilled with such a drilling tool.
There is also a known drilling tool that has a single magazine in which the lengths of pipe of the drill column and the casing are arranged concentrically, one inside the other. A disadvantage of this system is that the lengths of pipe for the drill column and for the casing are unnecessarily long. This complicates the design of the drilling tool and therefore makes it unnecessarily expensive. The concentrically arranged drill column pipes and borehole casing pipes ar taken from the magazine together by a double-head drive for drilling and are transferred to the borehole. After drilling the borehoie, each length of pipe of the drill column must be transferred back to the magazine before the prestressed ground anchorage can be introduced. After the anchor has been introduced, each length of pipe of the drill column is removed from the magazine and then returned to the magazine once again with the length of casing in a concentric arrangement. Returning the length of pipe of the drill column and the casing back to the magazine is tedious and time-consuming, and furthermore, a special drive is necessary for the lengths of pipe.
Known prior art structures always start with designs using a single magazine (see, for example German Patent 24 35 535 C2, German Utility Patents 18 88 205, 87 14 952 U1, U.S. Pat. Nos. 4,897,009, 3,493,061, and Soviet Patent 785,460). This single magazine is used for lengths of pipe for the drill column, so the effectiveness of these known devices is not great.
The present invention solves the problem of providing an apparatus and drilling method for producing boreholes in soil or rock where said apparatus permits simpler handling of the lengths of pipe for the drill column and for the casing and also permits a simpler and therefore less expensive design for the drilling tool. An unnecessary structural height of the drilling tool thereby is avoided.
The invention also provides the advantage that the lengths of pipe of the drill column and the casing can be removed from a magazine separately from each other and in chronological succession and then can be returned to the magazine after drilling the hole for the prestressed ground anchorage. The operation of supplying the lengths of pipe of the drill column and the casing to the magazine is simplified by the present invention.